Patent GB-438678-A (GB)
Title: Back racking mechanism for fashioning knitting machine of straight bar type
IPC: D04B11/06
Filed: 1934-09-08
Abstract: 438,678. Knitting-machines. WILDMAN MFG. CO., Norristown, Pennsylvania, U.S.A.- (Assignees of Howie, K.; Norristown, Pennsylvania, U.S.A.) Sept. 8, 1934, No. 25904. Convention date, Nov. 8, 1933. [Class 74 (ii)] A straight bar machine having narrowing point carriers and yarn carrier stops which are adjusted automatically during the fashioning operation is provided with mechanism for automatically restoring those members to their initial positions on completion of a stocking blank. The invention is described in connection with a machine of the type set out in Specifications 396,280 and 411,517, yarn carrier stops 36, Fig. 5, and narrowing point carriers 44<a> being moved inwardly during fashioning by screw shafts 43, 44b respectively which are driven by stub shafts 43<c>, 44<x>. The stub shafts are rotated intermittently by pawl-and-ratchet mechanism operated through steel bands 43<e>, 44e, Fig. 2, by a cam operated lever 43<g>, the loosely mounted pawl carrying drums 43d, 441 being returned to initial position after each stroke by means of springs 43<x>, 44<y>. When the narrowing operation is completed, a pattern drum A, acting through a rock shaft 1 and lever connections 2, 3, 4, operates a fork 6 to move a roller 7 into the path of a cam 8 which then imparts a reciprocating movement to a lever 9. The lever 9 is connected to a link 10 from which extends a chain 10<a>, and, beyond, a spring 10<b>, which is anchored to the frame, the chain engaging a sprocket 12, Fig. 5, on a bevel gear 13 loosely mounted on the shaft 43<c>. The gear 13 meshes with a bevel pinion 14 on a shaft 15 which has a gear engaging a crown gear 17 loosely mounted on the shaft 44<x>. The wheels 13, 17 carry pawls 13<a>, 17<a>, Figs. 10 and 12 for engagement with single tooth ratchets 13<c>, 17<c> fixed to their respective shafts 43<c>, 44<x>. Each pawl is controlled by a shield 13d or 17d pivotally mounted on the appropriate shaft and operated by the carrier blocks of the yarn carriers or the narrowing points towards the end of the back racking operation to remove the pawls from the ratchets 13<c> and 17<c>. The shield 13<d> is operated by a rod 31 on the yarn carrier blocks 36 engaging a pivoted lever 31b and actuating an arm 31d which by means of tail extension 13<f> rotates the shield 13d against the action of a spring 13x to raise the pawl 13<a> from the ratchet. As the carrier block 36 moves inwards during narrowing &c. the pawl is allowed to move into engagement with the ratchet. The shield 17d is controlled by the right narrowing point carrier block 44<a>, Fig. 5, which, on being moved to the right during back racking, engages a lug 29 and moves a rod 25 to bring a cam portion 24, Fig. 10 into contact with an arm 23 of a spring controlled lever 19. On rotation of the lever 19 the shield 17<d> is turned to mask the ratchet 17<c> and thereby render the pawl 17<a> ineffective. The shield is returned to normal position by a spring 30 during the narrowing operation. The pawl and ratchet mechanism driving the screw shafts is rendered inoperative during back racking, and while forming picot, by the action of a cam 24b on a pawl controlling lever 35.